Liquid lead stabilizers for vinyl chloride polymers and copolymers

ABSTRACT

Stabilization of vinyl chloride polymers and copolymers against heat or light decomposition and composition for use in the practice of same wherein the composition is formed of a solution of a basic lead salt having the general formula (RCOO)2Pb.nPbO, in which R is a branched-chain alkyl radical having from seven to 12 carbon atoms and n is a number of from 0.5 to 2 and in which solution is in a hydrocarbon solvent having a boiling point within the range of 100* to 180* C. or in a plasticizer ester.

United States Patent Roussos et al.

LIQUID LEAD STABILIZERS FOR VINYL CHLORIDE POLYMERS AND COPOLYMERSInventors: Michel Roussos, Lyon; Yves Bourgeois,

Paris, both of France Assignee: Melle-Bezons, Melle (Deux-Sevres),

France Filed: Apr. 25, 1968 Appl. No.: 724,274

Foreign Application Priority Data Apr. 27, 1967 France ..104340 US. Cl...252/400, 252/407, 260/45.75 R, 260/435 Int. Cl. ..C08i 45/62 Field ofSearch ..252/400, 407; 260/45.75, 435; 44/66 Primary Examiner-Richard D.Lovering Assistant Examinerlrwin Gluck Attorney-McDougall, Hersh, Scott& Ladd [57] ABSTRACT Stabilization of vinyl chloride polymers andcopolymers against heat or light decomposition and composition for usein the practice of same wherein the composition is formed of a solutionof a basic lead salt having the general formula (R- COO) Pb.nPbO, inwhich R is a branched-chain alkyl radical having from seven to 12 carbonatoms and n is a number of from 0.5 to 2 and in which solution is in ahydrocarbon solvent having a boiling point within the range of 100 to180 C. or in a plasticizer ester.

12 Claims, No Drawings LIQUID LEAD STABILIZERS FOR VINYL CHLORIDEPOLYMERS AND COPOLYMERS This invention relates to the stabilization ofvinyl chloride polymers and copolymers against decomposition in thepresence of light and heat and to a new and improved stabilizer for usein same.

It is known that vinyl chloride polymers and copolymers decompose underthe action of light and heat. This phenomenon results in discolorationof the product and degradation of its mechanical properties. It is forthis reason that it becomes necessary to effect stabilization of suchproducts before cure. More particularly, it is known that polyvinylchloride and copolymers thereof can be protected by means of leadstabilizers.

Conventional lead stabilizers are mainly basic lead salts derived fromorganic or inorganic acids. They are available, for the most part, insolid form such as powders or pastelike form. The use of powdered leadstabilizers necessitates severe safety precautions. To avoid suchinconveniences, it has been proposed to add various amounts ofplasticizer so as to reduce dusting and produce a paste. Such pasteshave a strong tendency to decant and are therefore difficult to measureout, whereby their use becomes impractical.

Liquid lead stabilizers are known. Conventional stabilizers of the typedescribed are neutral salts derived from organic acids, i.e., incontradistinction with the so-called basic" solid lead stabilizers, theycontain no basic PbO group capable of acting as an acceptor for thehydrochloric acid formed by the decomposition of the polymer and,accordingly, are less efficient. These liquid salts can be representedby the formula (R- COO) Pb, whereas most of the solid lead saltstabilizers are represented by the formula (R'COO) Pb.nPbO, n being from1 to 4. The liquid form of these products is obtained by the use oforganic acids of special constitution and of solvents.

An object of this invention is to provide a lead stabilizer which isboth basic and in liquid form.

In accordance with the practice of this invention, use is made of leadsalts of the general formula (RCOO) Pb.nPbO in which R is abranched-chain alkyl radical having from seven to 12 carbon atoms and nis a number, integer or not, of from 0.5 to 2.

The acids suitable for preparing the lead salts used in accordance withthis invention are organic acids, the basic lead salts of which can bedissolved in organic media, i.e., solvents or plasticizers. Thesolubility of these salts in such organic media is a function of thebranched character of the hydrocarbon chains of the acid radicals. Thepresence of a branchedchain and a minimum length of the chain areimportant. The following are given by way of iilustration, but not byway of limitation, namely: 3,5,5-trimethyl hexanoic acid, the commercial isononanoic acid which contains above 90 percent of3,5,5-trimethyl hexanoic acid, and the branched-chain, saturated,aliphatic acids containing eight to 10 carbon atoms in the molecule, asproduced by the x0 synthesis.

The salts used in accordance with the invention are produced by reactingthe above-defined acids with a lead oxide or hydroxide, preferablylitharge. The reaction is carried out in the presence of a liquid,organic water entrainer of con ventional kind, which azeotropicallyentrains the reaction water. Then, the water entrainer is displaced andreplaced by a hydrocarbon solvent or a plasticizer of higher boilingpoint. For this purpose there may be used, for example, a hydrocarbonsolvent boiling from 100 to 180 C., such as White Spirit, or a higherdialkyl phthalate, such as di (2-ethyl hexyl) phthalate, or didecylphthalate produced by the 0x0 synthesis, or 2- ethyl hexylepoxystearate. It is also possible to further add for admixture with thesolvent a 2-alkoxyethanol such as 2-butoxycthanol or a 2-alkoxypropanol,or dipropylene glycol, in an amount to make up 3 percent to 25 percentby weight of its mixture, to reduce the viscosity and make thedissolution easier. The products of the invention are suitable toprepare synergistic compositions which especially may contain achelating agent, such as an organic phosphite ester, more par- EXAMPLE 1This example illustrates the preparation of monobasic lead salt of 0x0 C-C acids, dissolved in di(2-ethyl hexyl) phthalate.

The characteristics of the 0x0 C -C acids are as follows:

Molecular weight reckoned from the acidity Specific weight at 20' C.Boiling range at atmospheric pressure,

from 5 to distilled off Viscosity at 20 C. iodine number 228 to 244 C.l0 centipoises i 1 Into a reaction vessel of 3 liters capacity there isintroduced, by weight, 250 parts of gasoline E as a water-entrainer, 336parts (2 moles) of 0x0 C -C, acids and, at a temperature of 50 C., 226parts 1 mole) of litharge. The mixture is heated to and maintained at C.for 1 hour. Then, after cooling, there is added 171 parts of dipropyleneglycol and a paste made of 226 parts of litharge and 30 parts ofisobutanol. The resulting mixture is boiled under reflux for 2 hours,then the water is distilled ofi" azeotropically. Twenty-four parts ofaque ous phase is collected. The gasoline is distilled off under anabsolute pressure of 80 mm. Hg. When the temperature of the mixture inthe vessel reaches 80 C., there is gradually added thereto an amount ofdi(2-ethyl hexyl) phthalate to keep the mixture fluid. The distillationis continued up to a temperature of C. Addition of di(Z-ethyl hexyl)phthalate is then continued while the temperature decreases. Sevenhundred and seventy-one parts of di(2-ethyl hexyl) phthalate will havebeen introduced. The mixture is filtered under pressure and there isobtained 1,688 parts of a liquid having the following characteristics:

Lead by weight) Viscosity at 25 C.

23.7(calculaled1241) 4.l poises.

EXAMPLE 2 This example illustrates the preparation of a similar leadsalt but with 1.5 PbO, in substantially the same manner as in Example lbut using the following substances (parts by weight):

Gasoline E 220 parts Oxo C,,--C acids 296 parts l .76 moles) Litharge497 parts (2.2 moles) lsohutanol 27 parts Dipropylene glycol l73 partsDi (Z-ethyl hexyl) phthalate 776 parts There is finally obtained 1,717parts of a liquid having the following characteristics:

Lead (1: by weight) Viscosity at 25 C.

25.5 (calculated: 26.4) 415 poises.

EXAMPLE 3 Gasoline E 220 Parts The following resinous mass was used(parts by weight): Oxo C -C acids 296 parts (1.76 moles) Litharge 497parts (2.2 moles) lsobmanm 27 pans Polyvinyl chloride produced byoipmpylene g|yc| 7 pans mass process (Lucovyl GB 9550) I parts 2-ethylhexyl epoxystearate 776 parts Y Pmhalme so P There is finally obtained1,697 parts of a liquid having th The stabilizers used in the variousmixtures tested were as following characteristics: follOWSi Lead byweight) 24.9 (calculated: 26.4) Mimrc stabilizer Viscosity at 25 Cv 1.8poises.

Kind Parts (check-test) None l EXAMPLE 4 z Dibasic lead phthalate 0.5 3Dibasic lead phthalate I This example illustrates a composltloncontalnlng dlphenyl 4 Dibasic lead stearate 0.8 monodecyl phosphite.This composition is obtained by mixing, 2 g '2 "2 b I at 60 C., 100parts by weight of the final liquid produced in 7 omposmo (see c OW) C m't' (A) (see below) 4.4 Example 3 wlth 45 parts by weight of dlphenylmonodecyl ...:i.iZ: below) 2.1

phosphite. The characteristics of the composition are as fol- C mp siion (B) l 5.4 l 0 Composition (C) (see below) 3.2 I Composition (C) (seebelow) 6.4

Lead by weight) 17.2 A viscosiy a 251: C. 09 poises Stablllzlngcomposltlon (A) comprlses:

lpart by weight ot'diphenenyl monodecyl phosphite EXAMPLE 5 3 parts byweight of monobasic lead salt of 0x0 C -C acids, dissolved at 45 percentconcentration in a mixture ofWhite Spirit and dipropylene glycol.

This example illustrates the preparatlon of monobaslc lead salt ofisononanoic acid, dissolved in Oxo didecyl phthalate.

The characteristics of the isononanoic acid used are as fol- 2 parts byweightof Z-cthyl hexylepoxystcarate lows: 3O

3 parts by weight of monobaslc lead salt of 0x0 C C aclds, dlssolved at45 percent conccntration in a mixture ofWhite Spirit and dipropyleneglycol.

Stabilizing composition (B) comprises:

Molecular weight reckoned from the acidity [6| Stabilizing composition(C) comprises: 2 pans by weight of Z-clhyl hexyl epox- S e ifi i ht at20 C, (1395 ystearate 2 parts by weight of 1.5 basic lead salt of 0x0 CC acids. dissolved C l (H at 45 percent concentration in a mixtureofWhite Spirit and dipropylene glycol. Boiling range at atmosphericpressure, from 5 to 95% distilled Off m The amounts of stablllzers usedare such that they represent Viscosity at 20C. ll Cenlilwises the samelead content in mixtures Nos. 2, 4, 6, 8 and 10 and I twice this contentin mixtures Nos. 3, 5, 7, 9 and l l. The operation ls carried outsubstantially as described in 0 Th curing f h mixtures i performed i B mff 1i Example It the starting Substances being as follows (P y ders. Theheat stability tests are carried out at 180 C. in a weight)! heated roomwith natural ventilation. The results of the tests, Gasolincg 124mmgiven in Table l, are expressed with reference to an iodine lsononanoicacid lll parts (1 mole) SCfli.

TABLE I Mixtures Time (hours) 1 2 3 6 l) 10 11 Lilharsc 226 Parts (1 Itis thus seen that, for a same lead content, the three liquid gz l z ICol 5 22: compositions, A, B, and especially C, exhibit better results 3g 377 thle he1cl} l-mixtured 2lt)nd tlh;d mixtures stabilized with Thereis finally obtained 838 parts of a liquid having the foli aslc ea p t aate or I e Stearate' lowin characteristics:

g EXAMPLE 7 Lead ()6 by weight) 23.3 (calculated: 24.7) Viscosity m 25(2 4.9 poises. Experiments slmllar to those of example 6 are carriedout, but there is substituted for the polyvinyl chloride produced byEXAMPLE 6 u u mass process a polyvlnyl chloride produced by suspenslonThls example illustrates comparative stabilization experiprocess,"namely, Lucovyl" GS I200. The results of the tests ments. are given inTable ll.

TABLE 11 Mixtures 'limo (hours) 7 8 9 10 11 0, 0 0 0 0 V4 0 0 0 0 0 {/1o 2 5 2 H 0 5 5 5 5 l 0 10 20 10 5 50 10 50 10 1o 50 10 50 10 u," 201,000 10 200 10 2... a0 20 500 10 2%". 1,000 50 1,000 20 2%, 200 20 2%000 160 3 1,000 200 It is still seen that compositions A, B and Cexhibit better 3. A solution as claimed in claim 1 in which the salt isresults than the other ones. derived from isononanoic acid.

. 4. A solution as claimed in claim 1 in which the salt is EXAMPLE 8derived from a mixture of acids having from eight to l0 car- Experimentssimilar to those of Example 6 are carried out, bon atoms and produced bythe 0x0 synthesis.

but there is substituted for the polyvinyl chloride produced by 5. Asolution as claimed in claim 1 in which the salt has the mass process" apolyvinyl chloride produced by emulsion general formula (RCOO) Pb.PbO.

process, namely, Lucovyl PE 1805. The results of the tests 6. A solutionas claimed in claim 1 in which the salt has the are given in Table Ill.7 general formula (RCOOhPb. LSPbO.

TABLE 111 Mixtures Time (hours) 1 2 3 4 5 6 7 8 1) 10 11 It is stillseen that compositions A, B and C exhibit better 7. A solution asclaimed in claim 1 in which the solvent is results than the other ones.mineral spirits.

In the foregoing examples the Lucovyl resins are marketed 8. A solutionas claimed in claim 1 in which the solvent is a in France byPechiney-Saint-Gobain. higher dialkyl phthalate.

It will be apparent from the foregoing that we have provided 9, A l ti nas l imed i claim 1 i whi h the solvent is 2- a new and improvedstabilizer and composition for vinyl ethyl hexyl epoxystearate. chloridepolymers and copolymers. 10. In solution in a hydrocarbon solvent havinga boiling It will be understood that changes may be made in h pointwithin the range of 100 to 180 C. or in a plasticizer details offormulation and application without departing from e ter, forstabilization of vinyl chloride polymers and the spirit of theinvention, especially as defined n the fOlIOW- copolymers, an effectiveamount of a basic lead salt having the ing claimsgeneral formula (RCOO)Pb.nPbO in which R is a branched- We claim: chain alkyl radical havingfrom seven to 12 carbon atoms and 1- in Soluti n in a hyd Solvent h g aboiling n is a number from 0.5 to 2, and a compound selected from pointwithin the range of 100 to 180 C. or in a plasticizer h group consistingf zlk y tha l, 2 lkoxy ol ester, for siabililatiofl of Vinyl chloride Py and and dipropylene glycol present in an amount of 3 to 25percopolymers, an effective amount of a basic lead salt having the centb i h f hi mixture i h h l g n formula (Rcoohpbnpdo in which R is abranchedll. A solution as claimed in claim 10 which includes a diarylchain alkyl radical having from seven to 12 carbon atoms and lkphogphite ester,

n is a number from .5 t0 2- 5 5 12. A solution as claimed in claim 1which includes an or- 2. A solution as claimed in claim 1 in which thesalt is ganic i id i the f f h l, derived from 3,5,5-trimethylhexanoicacid.

2. A solution as claimed in claim 1 in which the salt is derived from3,5,5-trimethyl hexanoic acid.
 3. A solution as claimed in claim 1 inwhich the salt is derived from isononanoic acid.
 4. A solution asclaimed in claim 1 in which the salt is derived from a mixture of acidshaving from eight to 10 carbon atoms and produced by the Oxo synthesis.5. A solution as claimed in claim 1 in which the salt has the generalformula (RCOO)2Pb.PbO.
 6. A solution as claimed in claim 1 in which thesalt has the general formula (RCOO)2Pb.1.5PbO.
 7. A solution as claimedin claim 1 in which the solvent is mineral spirits.
 8. A solution asclaimed in claim 1 in which the solvent is a higher dialkyl phthalate.9. A solution as claimed in claim 1 in which the solvent is 2-ethylhexyl epoxystearate.
 10. In solution in a hydrocarbon solvent having aboiling point within the range of 100* to 180* C. or in a plasticizerester, for stabilization of vinyl chloride polymers and copolymers, aneffective amount of a basic lead salt having the general formula(RCOO)2Pb.nPbO in which R is a branched-chain alkyl radical having fromseven to 12 carbon atoms and n is a number from 0.5 to 2, and a compoundselected from the group consisting of 2-alkoxyethanol, 2-alkoxypropanoland dipropylene glycol present in an amount of 3 to 25 percent by weightof this mixture with the solvent.
 11. A solution as claimed in claim 10which includes a diaryl alkyl phosphite ester.
 12. A solution as claimedin claim 1 which includes an organic antioxidant in the form of aphenol.